1. Field of the Invention
The present invention relates to a transmission control system of a vehicle and a vehicle including the same.
2. Description of the Related Art
Conventionally, there have been developed automatic or semi-automatic transmission control systems capable of automatically changing a gear ratio of a transmission. In such a transmission control system, the gear ratio is generally changed at a preset suitable speed. This prevents an occurrence of a shift shock in a vehicle.
In the vehicle in which the gear ratio is changed at the preset speed, the gear ratio of the transmission cannot be quickly changed even though a driver desires a quick speed change.
Therefore, a transmission control device of a stepless transmission described in JP 9-53712 A, for example, is provided with an automatic speed change mode and a manual speed change mode. The rate of change of the gear ratio in the manual speed change mode is set faster than that in the automatic speed change mode. Thus, the driver operates a speed change lever in the manual speed change mode to enable a quick speed change operation of the transmission in the vehicle including the transmission control device.
In the foregoing transmission control device, however, the driver operates the speed change lever in the manual speed change mode to always cause the gear ratio to be quickly changed. In other words, the speed change operation is quickly performed even when the driver does not desire the quick speed change operation. This leads to degradation of drivability of the vehicle.